Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
  • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
  • H01R13/66—Structural association with built-in electrical component
  • H01R13/6608—Structural association with built-in electrical component with built-in single component
  • H01R13/6625—Structural association with built-in electrical component with built-in single component with capacitive component
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/0213—Electrical arrangements not otherwise provided for
  • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/14—Structural association of two or more printed circuits

Definitions

• Computing systems are usually made up of assemblies that exchange data with one another. These assemblies are pluggable on a carrier plate and the contacts of the different connectors are connected to each other. This results in a large number of parallel lines via which a corresponding amount of data can be transmitted in one transmission operation. In addition to these data lines, there are control lines, ground lines and power supply lines.
• An asymmetrical control is often used for the transmission, in which one data line is used per logic signal and is switched with respect to a common ground.
• electronic switches are used which connect a potential provided on the data line to a ground line. Because of the inductances and capacitances on the signal lines, there are slow edges or vibrations when switching on or off. This effect can be avoided if the signal lines are terminated with their characteristic impedance.
• a common plug contact is used for the ground connection of many signal lines. Since considerably higher high-frequency currents flow over the one or a few ground contacts than over the many signal contacts, this happens Disorders.
• a known measure in high-speed applications is therefore the use of one ground contact per signal contact. This solution is ruled out if, for reasons of compatibility, a standardized contact assignment must be used, in which the number of ground contacts is fixed.
• the invention is based on the consideration that, in addition to the high-frequency overloaded plug contacts for the signal ground, there is a considerable number of plug contacts for the power supply, these are not loaded with high frequencies and can therefore serve to relieve the contacts for signal ground.
• a first solution is to use the contacts of the voltage supply as an additional high-frequency path via capacitors.
• a high-frequency connection from the voltage supply to the signal ground must be created on the module and the rear wall by means of capacitors. This requires a number of capacitors that is equal to the product of the number of slots and the number of power supply contacts. These capacitors must be connected to the plug contacts with little induction, that is, they must be attached directly next to them.
• the voltage supply on the rear wall must be high-frequency equivalent to the signal ground be carried out. This can be achieved if the signal lines with respect to the signal ground have the same shaft impedance as with respect to the voltage supply. Two embodiments could be determined for this.
• the conductor tracks in a multilayer printed circuit board for signal ground and voltage supply have the same layout and are in adjacent levels. The voltage supply is placed in an outer and the signal mass in the immediately adjacent plane and an insulating layer of the smallest possible thickness is used.
• the signal lines are routed on the opposite outer layer and separated from the above-mentioned levels by a much thicker insulating layer (of the same material).
• the distance from the signal lines to the signal ground and from the signal lines to the voltage supply is thus essentially the same, so that the waveguide impedance with respect to the two does not differ significantly.
• a capacitive connection between signal ground and voltage supply is only necessary at the ends where the terminating resistors for the signal waveguides are also arranged.
• the signal lines can be placed in a central position and signal mass and voltage supply can be routed in the two outer layers. This solution is used when the insulating layer between the signal conductor and the signal ground is already quite thin and a much thinner layer between the signal ground and the voltage supply can no longer be produced.
• the invention therefore ensures that the power supply is also included in the waveguide of the signal lines.
• the capacitors on the plug contacts on the rear wall are then unnecessary; the desired effect is achieved by the layout of the rear wall implemented as a printed circuit.
• the invention can advantageously also be applied to a module itself.
• the electronic switches are located away from the connector contacts.
• the signal lines, the signal ground and the supply voltage are routed with the same characteristic impedance between the signal line and signal ground and between the signal line and supply voltage as on the rear wall.
• an AC coupling must be set up directly at the switch, in particular a low-inductance capacitor must be connected between the signal ground and the supply voltage.
• Such a capacitor is usually already available to buffer the supply voltage. This means that additional capacitors are no longer necessary because the acceleration of the signal transmission is achieved solely by the clever arrangement of the conductor tracks.
• the invention therefore consists in the fact that in a system with modules, power supply, signal transmission via closed signal lines and signal ground, the impedance of the signal lines with respect to both the signal ground and the voltage supply is the same, with an alternating current coupling of the contacts for signal ground and voltage ⁇ feeding takes place on the modules and near the termination of the signal lines.
• 1 is a simplified view of the back wall of a computer
• 3 shows a cross section through the rear wall with external signal lines and 4 shows a cross section through the rear wall with internal signal lines.
• a rear wall 10 is shown, which is shown for a better overview with only three headers 11a..c and nine contacts per header.
• the poles S are signal contacts which are each connected to one another by conductor tracks 13a.
• the poles G serve as ground poles and are connected to one another by ground connections.
• the poles V are used for supplying voltage and are connected to the operating voltage Ul via leads -15.
• the signal lines 13a..e are terminated at both ends by terminating resistors RL and RR.
• the left resistors RL and the right resistors RR are equal to one another and equal to the characteristic impedance of the signal lines 13 with respect to the signal ground 14. This is determined by the width of the signal line 13 and its electrical distance from the signal ground 14, which is derived from the dielectric constant of the PCB material and the spatial distance determined.
• This rear wall is operated as a bus system with an open collector structure, in which a LOW bit is signaled by connecting a signal line to ground and a high bit by omitting this connection.
• the terminating resistor is connected to a potential U2 in terms of DC voltage.
• FIG. 2 This situation is shown in Fig. 2 in its electrical effect.
• the parts are located on the rear wall outside the modules 20a and 20b framed by dashed lines.
• 11a and 11b denote the connectors fastened on the rear wall and 20a and 20b the modules contacted with them.
• 20a is a sending module
• 20b is a receiving module.
• the broadcast and shown Receiving means are present on all modules for all signal lines; this is simplified for the sake of clarity.
• a semiconductor switch 21a is arranged in the transmitting module 20a and is connected to a signal contact S and a signal ground 22a.
• the signal contact S is connected via line 13a to the two terminating resistors RL and RR, which in turn are connected to the voltage U2. If the semiconductor switch 21a is not active, the line 13a is at the potential U2. On the other hand, if the semiconductor switch 21a is active, the current indicated by the arrows and determined by the resistors RL and RR flows from the voltage source U2 through the resistors RL and RR, via the signal line 13a, through the contact S, through the semiconductor switch. 21a, along the ground line 22a in the module 20a, through the contact G and the ground line 14 back into the voltage source U2. This creates a potential close to ground on line 13a, which is evaluated by receiving module 20b with a receiving circuit 23a.
• the situation is different at the time of switching.
• the inductance of the contact pins is decisive here.
• a settling process occurs via the inductance of the contacts, which limits the maximum speed of bus use.
• the contacts for the voltage supply are also used in alternating current, so that the inductances of the contact pins are reduced by parallel connection.
• a capacitor is connected to each module and to each voltage supply contact V. sator 24 attached between this and signal ground.
• the contact V is also connected to the signal ground in an alternating current manner.
• a capacitor 31 is attached to each contact V.
• a significant improvement in which the capacitor 31 can be dispensed with is achieved in that the characteristic impedance of the signal line 13 in relation to the signal mass 14 is made equal to the characteristic impedance of the same signal line 13 in relation to the voltage supply 15. This is achieved when using a printed circuit board in that the layout of signal ground 14 and voltage supply 15 is designed essentially the same, and both have approximately the same electrical distance from the signal line 13.
• FIG. 4 shows an alternative embodiment in which the signal lines are shown in the middle ⁇ are classified. This form is advantageous if a low characteristic impedance is sought and the distance from the signal conductors 13 to the signal ground is therefore the smallest that can be produced. In addition, the interference radiation of the signal lines is shielded in this embodiment.
• the invention can advantageously also be applied to a module 20 when the electronic switches 21 are removed are arranged by the plug contacts.
• the signal lines 13, the signal ground 14 and the supply voltage 15 are routed as on the rear wall 20 with the same characteristic impedance between the signal line 13 and the signal ground 14 and between the signal line 13 and the supply voltage 15.
• the AC coupling on the module is achieved by an already existing blocking capacitor, so that the capacitor 24a close to the contacts can be omitted.
• the invention can also be used with connectors that are not designed as operationally releasable plugs, but also, for example, with modules that are soldered to a common carrier plate via contacts

Landscapes

• Details Of Connecting Devices For Male And Female Coupling (AREA)
• Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
• Structure Of Printed Boards (AREA)
• Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
• Glass Compositions (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Optical Integrated Circuits (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=6483460

Family Applications (1)

Country Status (6)

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Family Cites Families (5)

• 1993
  • 1993-03-22 DE DE4309147A patent/DE4309147A1/de not_active Withdrawn
• 1994
  • 1994-02-04 AT AT94906831T patent/ATE152263T1/de not_active IP Right Cessation
  • 1994-02-04 WO PCT/DE1994/000109 patent/WO1994022184A1/fr active IP Right Grant
  • 1994-02-04 DE DE59402537T patent/DE59402537D1/de not_active Expired - Fee Related
  • 1994-02-04 EP EP94906831A patent/EP0691041B1/fr not_active Expired - Lifetime
  • 1994-02-04 US US08/525,600 patent/US5652553A/en not_active Expired - Fee Related
  • 1994-02-04 JP JP6520485A patent/JPH08508833A/ja active Pending

Non-Patent Citations (1)

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